Stir together flour, baking powder, and salt. Set aside. In a large bowl cream butter and sugar until light. Add egg and beat until fluffy at low speed. Stir in flour mixture until dough is smooth. Stir in zucchini and nuts. Drop by round teaspoonful onto greased cookie sheet. Bake in preheated oven at 375 F for 15 to 20 minutes or until light brown. While warm, drizzle with Lemon Frost.